Infante Alfonso, Duke of Calabria

Infante Alfonso of Spain, Prince of the Two Sicilies, Duke of Calabria (30 November 1901 – 3 February 1964) was one of two claimants to the title of the head of the House of Bourbon-Two Sicilies from 1960 until his death in 1964. Alfonso was the son of Prince Carlos of Bourbon-Two Sicilies (1870–1949) and his wife Mercedes, Princess of Asturias (1880–1904). He was born and died in Madrid, Spain.

Alfonso's mother was Mercedes, Princess of Asturias, but she died in childbirth in 1904. King Alfonso XIII of Spain was unmarried at the time so as the Princess of the Asturias' eldest son, Alfonso became heir-presumptive to the Spanish crown, though, unlike his mother, he never held the title of Prince of Asturias. He was heir-presumptive until the birth of his cousin, Alfonso in 1907, to Alfonso XIII and Queen Victoria Eugenie.

Alfonso married Princess Alicia of Bourbon-Parma (1917-2017), his second cousin, daughter of Elias, Duke of Parma and Piacenza and his wife Archduchess Maria Anna of Austria, on 16 April 1936 in Vienna, Austria. Alfonso and Alicia had three children:

• Princess Teresa María of Bourbon-Two Sicilies (born 6 February 1937), married to Íñigo Moreno y Artega, Marqués de Laula, with seven children
• Infante Carlos, Duke of Calabria (16 January 1938 - 5 October 2015), married to Princess Anne of Orléans, with five children
• Princess Inés María of Bourbon-Two Sicilies (born 18 February 1940), married to Luis de Morales y Aguado, with five children

On the day after his birth (1 December 1901), his grandmother Queen Maria Christina conferred on him the Order of the Golden Fleece, the Collar of the Order of Charles III, and the Grand Cross of the Order of Isabella the Catholic.